With 2 weeks of non-usage, the battery will dro from 100 to around 60 percent. Is that normal? And at what percentage should i leave them if i wont use them for some time?

That's normal as the batteries are programmed to auto discharge to prevent damage if being stored for a while

If you look in the settings you can change the time from the default 10days

Any LIPO Battery should be keep balanced at 3.80Volts per cell for storage purposes. at that voltage the chemistry remains fairly stable and the degradation of the battery takes longer. Always remember to exercise the batteries charging them up and flying until you reach about 3.60Volt per cell.

Please read the manual...

Another one!!!  PLEASE READ THE MANUAL.

AACY: Thanks for your answer!
To the other two: You must be fun at parties.

Here is a video tutorial of battery maintenance for your reference:

TobH Posted at 2017-3-5 15:19
AACY: Thanks for your answer!
To the other two: You must be fun at parties.

No Problem! ;)